/**
 * Created by HP on 2017/7/31.
 */
window.onload=function(){
    var check_all=document.getElementById("check_all");
    var checks=document.getElementsByClassName("check");

    check_all.onclick=function(){
        for(var i=0;i<checks.length;i++)
        {
            checks[i].checked=this.checked;
        }
    }
}